The present invention generally relates to a lock mechanism for a hopper door, more particularly to an improved lock mechanism for mounting on both of the two outside hopper sheets adjacent double doors of railway hopper cars to open adjacent double doors simultaneously. The particular double door lock mechanism of the present invention improves the operational aspects of conventional double door locking arrangements by including a hook member that is pivotable so as to hook and hold the chute doors while also being slidable so as to close and lock the chute doors.
Generally, railway hopper cars are constructed to be emptied through a plurality of adjacent double doors located on the underside of the car whereby the bulk of the contents within the hopper car may be discharged therefrom through said doors and into a collecting area located below the railway tracks. Usually, the hopper cars are constructed with two doors, one accessible from one side of the train of cars, and another accessible from the other side of the cars. Often, a spreader bar is added for joining these adjacent double hopper doors to ensure that neither one of the doors will open until lock mechanisms provided on both of the outside hopper sheets are unlocked.
Previously known double door lock mechanisms include a pivotable hook that is actually a double hook in that it has one small recess which engages the spreader extension to hold the doors in the "catch" position and one larger recess to hold the door in a fully closed position. Two workmen generally work together from opposite sides of the hopper cars and swing the open adjacent double doors from the fully opened position to the "catch" position by pushing with one foot on the spreader bar extensions. In the "catch" position, the doors are open a few inches at their bottoms. Each man next places a long pry bar, usually about 5 feet long and 11/4 inch in diameter, through prying holes provided and then levers the doors to the fully closed position whereupon the larger recess on each hook drops into its working position. If the hook does not drop to the fully closed position, the workman hammers it there by using one end of his pry bar. Next, the workman moves a locking cam to the lock position and hammers it to the fully locked position with a hammer or an end of the pry bar. This type of locking cam arrangement has been found to fail on occasion when the entire hopper car is rotated for unloading.
To unlock this type of prior art double door lock, a workman drives the locking cam to the unlocked position and then drives the hook upwards to release the door. Sometimes the hook stays up momentarily, permitting the door to move to the fully opened position. At other times, the hook drops in time to hold the door in the "catch" position, in which case, the workman hammers the hook upwards to release the door. The hook is operated primarily by gravity, making the operation thereof somewhat dependent upon the particular orientation of the hopper car and the freedom with which the hook pivots about its pivot pin.
Another type of double door lock mechanism which attempts to improve upon the foregoing lock arrangement includes a lever, one end of which is attached to a spreader arm connecting the adjacent double doors, with the other end thereof being attached to a bell crank mounted on a shaft in such a manner that the lever, bell crank, and the shaft are in an overcenter relationship when the doors are closed. The operating shaft extends to each side of the car as does the locking shaft which operates locking cams, thereby permitting these mechanisms to be operated from either side of the car. However, these locking mechanisms are relatively expensive.
The present invention operates in a positive and sure manner when moving to the desired position, whether it be the fully closed, the "catch", or the fully opened position by providing a single-recess hook member that is both pivotable and slidable such that it pivots to properly locate the door as it moves from the fully opened position to the "catch" position or vice versa, while it also slides for movement between the "catch" position and the fully closed position. In the preferred embodiment, a latch is provided which is resistant to changes in gravitational forces brought about when the entire railway hopper car is rotated so that the hopper car doors will remain fully closed and locked even during such rotation.
It is, therefore, a general object of the present invention to provide an improved lock mechanism for a hopper door.
Another object of the present invention is to provide an improved double door lock mechanism for adjacent doors of a railway hopper car.
Another object of the present invention is to provide an improved double door hopper lock mechanism that operates in a positive and sure manner when moving to a desired position.
Another object of this invention is an improved lock mechanism for use on double doors of hopper railway cars that provides locking features independent of gravitational forces so as to maintain the locking engagements even when the railway cars are rotated.